1. Field of the Disclosure
The instant disclosure relates to a source driving circuit; in particular, to a source driving circuit which is compatible to a displayport interface or an embedded displayport (eDP) interface for a data or signal transmission.
2. Description of Related Art
In recent years, manufacturers have been in competition for specifications of laptops and tablets, from hard disk size, to central processing unit (CPU) speed, to an increase of screen resolution. Branded manufacturers not only equip their products with panels of an upgraded level from a (1,366×768) high-definition (HD) to a full high-definition (1,920×1,080), but also have begun to import a three-dimensional (3D) display function, which leads to a result that the image of traditional interface and design structure becomes less satisfying, and a more state-of-the-art digital interface is required for a high-speed video signal communication between a screen and the graphics processor (GPU), and is also required for supporting demand of a higher resolution. In comparison to a traditional LVDS interface, a digital eDP has a higher transferring rate, and is suitable for a high-resolution panel; the digital eDP interface also reduces the cable number so as to achieve a thin shaped design. In addition, the eDP utilizes the same protocol as DisplayPort so that it is possible to share an image outputting port of the GPU, and the specification of the latest generation of eDP 1.3 may further reduce power consumption of the GPU so as to extend the battery life significantly.
eDP is an interface especially designed for an embedded system, and is able to transfer large amounts of data with less pins, and provides great flexibility to a design of hardware mechanism, which not only releases more hinge designing space, but also greatly reduces complexity of the cable, suitable for a notebook computer, a tablet, or an All-in-one PC; in comparison to an exterior DisplayPort, the specification of the eDP is quite adjustable according to various scenarios. In particular, the eDP significantly improve defects of the LVDS so that there is no need for the GPU to reserve an image outputting port for an embedded display panel, and a Main Link Lane number and a data transferring rate may be adjusted according to a data transferring amount shown on a display panel; AUX Channel of the eDP also provides an extra channel for GPU to control a various parameter setting on a display panel.
However, if a timing controller is integrated to a source driver, a connecting method of the traditional LVDS does not work for a protocol of DP/eDP, and thus this inconsistent specification between new and old hardware may lead to a problem of incompatibility of hardware.